SMS blob online backup S lock

I have a simple SMS tablespace holding a table containing a blob. Nightly I have an online database backup executing. The first thing the backup does is lock the table containing the blob for X minutes with an S lock. It then moves on, releasing the table. Is there anyway around this so the table can be updated rather than just read due to the S lock? I'm running db2 9 fp 6 on zLinux.